package com.kty.entity;

import cn.hutool.core.date.DateUtil;

/**
 * 转码：
 * 公历、农历日期 互相转换
 */
public class ChineseCalendar {

    /**
     * 存储在农历 1901年-2100年 的每年的月日信息中，农历每月只能是29天或30天，
     * 一年内用12（或13）个二进制位表示，对应位置的1个表单为30天，否则为29天。
     */
    private static final int[] iLunarMonthDaysTable = {
            0x4ae0, 0xa570, 0x5268, 0xd260, 0xd950, 0x6aa8, 0x56a0, 0x9ad0, 0x4ae8, 0x4ae0, // 1910
            0xa4d8, 0xa4d0, 0xd250, 0xd548, 0xb550, 0x56a0, 0x96d0, 0x95b0, 0x49b8, 0x49b0, // 1920
            0xa4b0, 0xb258, 0x6a50, 0x6d40, 0xada8, 0x2b60, 0x9570, 0x4978, 0x4970, 0x64b0, // 1930
            0xd4a0, 0xea50, 0x6d48, 0x5ad0, 0x2b60, 0x9370, 0x92e0, 0xc968, 0xc950, 0xd4a0, // 1940
            0xda50, 0xb550, 0x56a0, 0xaad8, 0x25d0, 0x92d0, 0xc958, 0xa950, 0xb4a8, 0x6ca0, // 1950
            0xb550, 0x55a8, 0x4da0, 0xa5b0, 0x52b8, 0x52b0, 0xa950, 0xe950, 0x6aa0, 0xad50, // 1960
            0xab50, 0x4b60, 0xa570, 0xa570, 0x5260, 0xe930, 0xd950, 0x5aa8, 0x56a0, 0x96d0, // 1970
            0x4ae8, 0x4ad0, 0xa4d0, 0xd268, 0xd250, 0xd528, 0xb540, 0xb6a0, 0x96d0, 0x95b0, // 1980
            0x49b0, 0xa4b8, 0xa4b0, 0xb258, 0x6a50, 0x6d40, 0xada0, 0xab60, 0x9370, 0x4978, // 1990
            0x4970, 0x64b0, 0x6a50, 0xea50, 0x6b28, 0x5ac0, 0xab60, 0x9368, 0x92e0, 0xc960, // 2000
            0xd4a8, 0xd4a0, 0xda50, 0x5aa8, 0x56a0, 0xaad8, 0x25d0, 0x92d0, 0xc958, 0xa950, // 2010
            0xb4a0, 0xb550, 0xb550, 0x55a8, 0x4ba0, 0xa5b0, 0x52b8, 0x52b0, 0xa930, 0x74a8, // 2020
            0x6aa0, 0xad50, 0x4da8, 0x4b60, 0x9570, 0xa4e0, 0xd260, 0xe930, 0xd530, 0x5aa0, // 2030
            0x6b50, 0x96d0, 0x4ae8, 0x4ad0, 0xa4d0, 0xd258, 0xd250, 0xd520, 0xdaa0, 0xb5a0, // 2040
            0x56d0, 0x4ad8, 0x49b0, 0xa4b8, 0xa4b0, 0xaa50, 0xb528, 0x6d20, 0xada0, 0x55b0  // 2050
    };

    /**
     * 保留从 1901-2050年 的农历闰月，如果它不是0，则每个字节存储两年
     */
    private static final char[] iLunarLeapMonthTable = {
            0x00, 0x50, 0x04, 0x00, 0x20, // 1910
            0x60, 0x05, 0x00, 0x20, 0x70, // 1920
            0x05, 0x00, 0x40, 0x02, 0x06, // 1930
            0x00, 0x50, 0x03, 0x07, 0x00, // 1940
            0x60, 0x04, 0x00, 0x20, 0x70, // 1950
            0x05, 0x00, 0x30, 0x80, 0x06, // 1960
            0x00, 0x40, 0x03, 0x07, 0x00, // 1970
            0x50, 0x04, 0x08, 0x00, 0x60, // 1980
            0x04, 0x0a, 0x00, 0x60, 0x05, // 1990
            0x00, 0x30, 0x80, 0x05, 0x00, // 2000
            0x40, 0x02, 0x07, 0x00, 0x50, // 2010
            0x04, 0x09, 0x00, 0x60, 0x04, // 2020
            0x00, 0x20, 0x60, 0x05, 0x00, // 2030
            0x30, 0xb0, 0x06, 0x00, 0x50, // 2040
            0x02, 0x07, 0x00, 0x50, 0x03  // 2050
    };


    /**
     * 存储 1901年-2050年 太阳历和农历新年的偏移天数
     */
    private static final char[] iSolarLunarOffsetTable = {
            49, 38, 28, 46, 34, 24, 43, 32, 21, 40, // 1910
            29, 48, 36, 25, 44, 34, 22, 41, 31, 50, // 1920
            38, 27, 46, 35, 23, 43, 32, 22, 40, 29, // 1930
            47, 36, 25, 44, 34, 23, 41, 30, 49, 38, // 1940
            26, 45, 35, 24, 43, 32, 21, 40, 28, 47, // 1950
            36, 26, 44, 33, 23, 42, 30, 48, 38, 27, // 1960
            45, 35, 24, 43, 32, 20, 39, 29, 47, 36, // 1970
            26, 45, 33, 22, 41, 30, 48, 37, 27, 46, // 1980
            35, 24, 43, 32, 50, 39, 28, 47, 36, 26, // 1990
            45, 34, 22, 40, 30, 49, 37, 27, 46, 35, // 2000
            23, 42, 31, 21, 39, 28, 48, 37, 25, 44, // 2010
            33, 23, 41, 31, 50, 39, 28, 47, 35, 24, // 2020
            42, 30, 21, 40, 28, 47, 36, 25, 43, 33, // 2030
            22, 41, 30, 49, 37, 26, 44, 33, 23, 42, // 2040
            31, 21, 40, 29, 47, 36, 25, 44, 32, 22  // 2050
    };

//**********************************************************************************************************************

    /**
     * 判断平闰年
     *
     * @param iYear
     * @return
     */
    public static boolean bIsSolarLeapYear(int iYear) {

        return (DateUtil.isLeapYear(iYear));

    }

//----------------------------------------------------------------------------------------------------------------------

    /**
     * 阳历月份中的几天
     *
     * @param iYear
     * @param iMonth
     * @return
     */
    public static int iGetSYearMonthDays(int iYear, int iMonth) {

        if (((iMonth == 1) || (iMonth == 3) || (iMonth == 5) || (iMonth == 7) || (iMonth == 8) || (iMonth == 10) || (iMonth == 12))){
            return 31;
        } else if (((iMonth == 4) || (iMonth == 6) || (iMonth == 9) || (iMonth == 11))){
            return 30;
        } else if ((iMonth == 2)){
            if ((bIsSolarLeapYear(iYear))){
                return 29;
            } else return 28;
        } else return 0;

    }

//----------------------------------------------------------------------------------------------------------------------

    /**
     * 从新年到阳历中指出的日期的抵消天数
     *
     * @param iYear
     * @param iMonth
     * @param iDay
     * @return
     */
    public static int iGetSNewYearOffsetDays(int iYear, int iMonth, int iDay) {

        int iOffsetDays = 0;

        for (int i = 1; i < iMonth; i++) {
            iOffsetDays += iGetSYearMonthDays(iYear, i);
        }
        iOffsetDays += iDay - 1;

        return iOffsetDays;

    }

//----------------------------------------------------------------------------------------------------------------------

    /**
     * @param iYear
     * @return
     */
    public static int iGetLLeapMonth(int iYear) {

        char iMonth = iLunarLeapMonthTable[(iYear - 1901) / 2];

        if (iYear % 2 == 0)
            return (iMonth & 0x0f);
        else
            return (iMonth & 0xf0) >> 4;

    }

//----------------------------------------------------------------------------------------------------------------------

    /**
     * @param iYear
     * @param iMonth
     * @return
     */
    public static int iGetLMonthDays(int iYear, int iMonth) {

        int iLeapMonth = iGetLLeapMonth(iYear);
        if ((iMonth > 12) && ((iMonth - 12) != iLeapMonth) || (iMonth < 0)) {
            System.out.println("Wrong month, ^_^ , i think you are want a -1, go to death!");
            return -1;
        }
        if ((iMonth - 12) == iLeapMonth) {
            if (((iLunarMonthDaysTable[iYear - 1901] & (0x8000 >> iLeapMonth)) == 0)) {
                return 29;
            } else return 30;
        }
        if (((iLeapMonth > 0) && (iMonth > iLeapMonth))) {
            iMonth++;
        }
        if (((iLunarMonthDaysTable[iYear - 1901] & (0x8000 >> (iMonth - 1))) == 0)) {
            return 29;
        } else return 30;

    }

//----------------------------------------------------------------------------------------------------------------------

    /**
     * 农历年的几天
     *
     * @param iYear
     * @return
     */
    public static int iGetLYearDays(int iYear) {

        int iYearDays = 0;
        int iLeapMonth = iGetLLeapMonth(iYear);

        for (int i = 1; i < 13; i++)
            iYearDays += iGetLMonthDays(iYear, i);
        if (iLeapMonth > 0)
            iYearDays += iGetLMonthDays(iYear, iLeapMonth + 12);
        return iYearDays;

    }

//----------------------------------------------------------------------------------------------------------------------

    /**
     * @param iYear
     * @param iMonth
     * @param iDay
     * @return
     */
    public static int iGetLNewYearOffsetDays(int iYear, int iMonth, int iDay) {

        int iOffsetDays = 0;
        int iLeapMonth = iGetLLeapMonth(iYear);

        if ((iLeapMonth > 0) && (iLeapMonth == iMonth - 12)) {
            iMonth = iLeapMonth;
            iOffsetDays += iGetLMonthDays(iYear, iMonth);
        }

        for (int i = 1; i < iMonth; i++) {
            iOffsetDays += iGetLMonthDays(iYear, i);
            if (i == iLeapMonth)
                iOffsetDays += iGetLMonthDays(iYear, iLeapMonth + 12);
        }
        iOffsetDays += iDay - 1;
        return iOffsetDays;

    }

//----------------------------------------------------------------------------------------------------------------------

    /**
     * ★阳历改为阴历
     *
     * @param iYear
     * @param iMonth
     * @param iDay
     * @return
     */
    public static String sCalendarSolarToLundar(int iYear, int iMonth, int iDay) {

        int iLDay, iLMonth, iLYear;
        int iOffsetDays = iGetSNewYearOffsetDays(iYear, iMonth, iDay);
        int iLeapMonth = iGetLLeapMonth(iYear);

        if (iOffsetDays < iSolarLunarOffsetTable[iYear - 1901]) {
            iLYear = iYear - 1;
            iOffsetDays = iSolarLunarOffsetTable[iYear - 1901] - iOffsetDays;
            iLDay = iOffsetDays;

            for (iLMonth = 12; iOffsetDays > iGetLMonthDays(iLYear, iLMonth); iLMonth--) {
                iLDay = iOffsetDays;
                iOffsetDays -= iGetLMonthDays(iLYear, iLMonth);
            }
            if (0 == iLDay)
                iLDay = 1;
            else
                iLDay = iGetLMonthDays(iLYear, iLMonth) - iOffsetDays + 1;
        } else {
            iLYear = iYear;
            iOffsetDays -= iSolarLunarOffsetTable[iYear - 1901];
            iLDay = iOffsetDays + 1;

            for (iLMonth = 1; iOffsetDays >= 0; iLMonth++) {
                iLDay = iOffsetDays + 1;
                iOffsetDays -= iGetLMonthDays(iLYear, iLMonth);
                if ((iLeapMonth == iLMonth) && (iOffsetDays > 0)) {
                    iLDay = iOffsetDays;
                    iOffsetDays -= iGetLMonthDays(iLYear, iLMonth + 12);
                    if (iOffsetDays <= 0) {
                        iLMonth += 12 + 1;
                        break;
                    }
                }
            }
            iLMonth--;
        }
        return "" + iLYear + (iLMonth > 9 ? "" + iLMonth : "0" + iLMonth) + (iLDay > 9 ? "" + iLDay : "0" + iLDay);

    }

//----------------------------------------------------------------------------------------------------------------------

    /**
     * ★农历改为阳历
     *
     * @param iYear
     * @param iMonth
     * @param iDay
     * @return
     */
    public static String sCalendarLundarToSolar(int iYear, int iMonth, int iDay) {

        int iSYear, iSMonth, iSDay;
        int iOffsetDays = iGetLNewYearOffsetDays(iYear, iMonth, iDay) + iSolarLunarOffsetTable[iYear - 1901];
        int iYearDays = bIsSolarLeapYear(iYear) ? 366 : 365;

        if (iOffsetDays >= iYearDays) {
            iSYear = iYear + 1;
            iOffsetDays -= iYearDays;
        } else {
            iSYear = iYear;
        }
        iSDay = iOffsetDays + 1;
        for (iSMonth = 1; iOffsetDays >= 0; iSMonth++) {
            iSDay = iOffsetDays + 1;
            iOffsetDays -= iGetSYearMonthDays(iSYear, iSMonth);
        }
        iSMonth--;

        return "" + iSYear + (iSMonth > 9 ? iSMonth + "" : "0" + iSMonth) + (iSDay > 9 ? iSDay + "" : "0" + iSDay);

    }


}
